My current backup solution for my media hard drive is to run Backup automatically every morning at 4am. While this is all find and dandy for now, eventually the incremental backups are going to fill up the backup drive, when all I really want and need is a mirrored copy of the media drive. I have two WD 640's for this. What I want to do is set up a simple RAID that creates a mirrored image of the media drive (the 1st WD 640) to a second drive (labeled Backup Drive, the 2nd WD 640). How do I go about setting this up without funking with the data that is currently on the media drive (Don't have enough internal or external storage to temporarily move it).